Tree Farmer,
Are you saying that companies who produce 4WD's (ATV's trucks, tractors, etc) are guilty of false advertising? The 3rd wheel IS driven. There is power going there right? You can't hold the manufacturer responsible for the fact the you may put the machine in a position where the wheel/tire is going to spin. If this machine were on level ground then is it still 2WD? Nothing has changed transfer case/tranny wise... It's still the same. The difference is the wheel now has something to "bite" on. Something is making the wheel spin. Therefore it can't be considered 2WD. If you use Gordons reasoning, then if no tire has sufficient traction to propel yourself foward or backward you would have "No wheel drive". Which isn't true, anyone knows that. The problem is simply a loss of traction, not a loss of "drive."
c-ya,

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Andrew Thomas

'99 Scrambler 400 & '99 Trailblazer, both with RCR mods.

 

Tree wrote
"When a wheel spins freely on a so-called limited slip differential, behaving exactly like an unlimited slip or open differential ,the only motive power for moving the quad comes from the two rear wheels."


This is a statement from an automobile manufacturer re: limited slip differentials "A limited slip differential has clutches which cause both wheels to theoretically spin at the same speed"


Another definition from a automotive magazine off the internet was
"LIMITED SLIP DIFFERENTIAL - A differential where the mechanism reacts to differences in torque when one wheel on an axle starts to slip, and LIMITS the differential action to maintain traction"

Please bear in mind that these are automotive applications.


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Ride the "WILD" Country, South Gillies, Ontario, Canada.

2000 Honda 450ES The "BIGGER BIG RED"



[This message has been edited by BigRed450 (edited 01-03-2000).]

 

Andrew, with the utmost of reluctance, I shall try responding to your post.

Why reluctant? Some while ago, extensive discussions regarding the design and operation of differentials generally, and "limited-slip" differentials particularly, greatly offended and even angered certain readers (you know who you are!).

I believe lots of misunderstanding arises because many do not distinguish between open differential action and limited-slip differential action. An open differential, or non-functioning/ineffective limited-slip differential, biases no significant torque to the wheel with traction when its mate spins. A PROPERLY-FUNCTIONING limited-slip differential biases a portion of the spinning wheel's torque to the wheel with traction.

First, I ask you, Andrew, to re-read my previous post carefully, paying particular attention to my comments regarding the different definitions possible for the word "drive" in the context, "three-wheel drive."

If "drive" means rotate a wheel under power, I conceded you have a point with your "three-wheel drive" label; however, if "drive" is defined as motive power to the quad, when a wheel breaks free and spins from open differential action, no appreciable motive power comes from the front wheel with traction, and no motive power at all comes from the spinning wheel. Therefore, by that definition, only two wheels are left providing motive power, the two rear wheels. I believe I just reiterated Gordon's point.

Do manufacturers advertise falsely, claiming "four-wheel drive" pickup trucks and soccer mom vans, vehicles with differentials BOTH front and rear?

No, but unless these "four-wheel drive" vehicles have PROPERLY-FUNCTIONING (e.g., properly torqued and surfaced clutch-packs) limited-slip or locking differentials, they become "no-wheel drive" machines, under the "motive power" definition, when one each front and rear wheel is free to spin. Such a vehicle (with open differentials), with one front and one rear wheel on dry pavement, and the other two wheels spinning, ain't going nowhere.

Thus is the nature of differentials, unless the differential (spider) gear driving the spinning wheel is forced into contact with the inner surface of the differential carrier through some clutch, cam, or sprag mechanism (the "limited-slip" part of differentials so designated), biasing torque to the opposite axle by . . . sorry, I didn't intend to get into design and functioning detail, in consideration of the tender sensibilities of those who might be offended by this discussion!

You're welcome, Pflueeb, Rosco and other grateful readers!

Tree Farmer



[This message has been edited by Tree Farmer (edited 01-03-2000).]

 

Without trying to get to technical. When I need 4WD, or AWD on my Xpedition, I flip the switch and go.

Brian

 

Tree,
I know what you are saying. All I'm saying is that you can't have a "no drive" viechle. Which under your definition is what you would have if you got stuck. What about an IH Scout with ARB's? All 4 wheels locked turning at the same rate of speed with the same amount of power applied to each wheel. BUT you are still stuck. Is that Scout "No-drive? If I were to ask you, you would say yes. Even though I see all 4 tires spinning. Like I said the wheels are driven, it's the mud/snow etc that causes the problem. If you have a transfer case that has a positive lock (not a viscous coupling) you CANNOT have 2WD drive. One of the front wheels is turning, no matter even it is just turning in the air. You can throw the definition of "drive" around all you want. Anyone who has ever driven a auto/tractor etc with a on/off diff. knows how it works. You seem to be confusing "drive" & "traction". If you are stuck in a mudhole & can't go foward because of a lack of traction (or as you call it drive) but yet you can back out because you have enough traction then what? You have reverse "drive" only tranny??? No you simply have enough traction behind you. I mean after all even though you may not have been moving foward your wheels were spinning right? It's just anyone who has ever drove a 4x4 certainly knows the difference between a wheel/tire not being powered and one not having traction. If you are stuck on a Honda with one tire in the air spinning and you are able to lean up enough for the front tire to contact the ground and move you foward what happened? Did you go from 2WD to 3WD? NO, you just added traction. Unless you somehow added a T-case, locking hub & a half-shaft in the span of a few seconds. When a tire is spinning on an auto, truck, ATV etc and the machine is not moving foward grab the spinning tire. Maybe only then when it attempts to use your arms/hands as "traction" you will see what driven means. I mean if your right and it's only 2WD only because it is stuck then you shouldn't get hurt... According to you a wheel is only "driven" when the viechle is moving foward. That means my 5.0 GT is 4WD when it goes down the road.

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Andrew Thomas

'99 Scrambler 400 & '99 Trailblazer, both with RCR mods.

 

Andrew, this semantic argument could go on forever; however, it won't, because I'm out of here.

I appreciate your understanding, but think you misunderstand and misquote me somewhat. In my opinion, you certainly mischaracterize my hypothetical responses to your hypothetical questions.

My F150 4X4 has a Detroit Locker rear end and an EZ Locker front end. When I become stuck in this vehicle (yes, it's possible!), I do not consider the vehicle a no-wheel drive one, because motive power is available to all four wheels, hapless as my predicament may be. Additional traction to any wheel might free the truck.

However, before I installed the lockers, and became stuck, with two wheels on one side spinning, I DID consider the vehicle in that particular configuration and situation a no-wheel drive vehicle because: no motive power was available to the wheels with whatever traction they had. As long as one wheel on each axle was spinning, no amount of additional traction to the stationary wheel would get the truck out, because the power was dissipated from each axle to its uselessly spinning wheel.

Now, maybe we don't disagree over physical functions; you look at the situation differently from the way I do in terms of words used to describe it and definitions chosen, essentially arbitrary choices.

Often, more than one way exists viewing or interpreting a situation. Yours may be more valid, better justified, and more sensible than mine. Maybe not.

Tree Farmer

 

****My F150 4X4 has a Detroit Locker rear end and an EZ Locker front end. When I become stuck in this vehicle (yes, it's possible!), I do not consider the vehicle a no-wheel drive one, because motive power is available to all four wheels, hapless as my predicament may be. Additional traction to any wheel might free the truck.
However, before I installed the lockers, and became stuck, with two wheels on one side spinning, I DID consider the vehicle in that particular configuration and situation a no-wheel drive vehicle because: no motive power was available to the wheels with whatever traction they had***

Tree,
Your arguing with yourself. You say it can't be "no drive" because all 4 are spinning, then you suggest it's no drive because only 2 wheels spin. If your 2 wheels are spinning they have motive power!!! I mean the wind can't be turning them. The problem was the traction available was mud/snow etc. Before your powertrain mods you could have called your truck a 2WD & technically been right. But you could not have called it a no-drive. The 2 wheels are going around in the mud, you are going nowhere. Now say somehow you pick your truck up & drop it on the road. You suddenly drive away. What changed??? The traction.
I haven't mischaracterized anything or misquoted you or whatever.
You can use all the big words, hypthetical situations in which one may get stuck, and interpetations you want. But it's really as simple as if 1,2,3,4+ wheels are turning something is making them turn. They are being "driven" somehow. Whether it is a Big Block Mopar or a hamster in a wheel. It is up to you as a driver/rider to keep the machine in a position to effectively use it's driven wheels, whether that be 1 wheel or 100 wheels.
I'm not trying to argue. You can use the different views thing to make yourself ( & maybe me) feel correct or at least on the right track and appease youself & maybe me too. But you can't argue that a spinning tire (stuck or not) is not driven.
c-ya,

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Andrew Thomas

'99 Scrambler 400 & '99 Trailblazer, both with RCR mods.

 

BigRed, on every 4x4 I've owned (and several others), I've performed the following test: Raise the machine to have all four wheels off the ground (ATV maintenance lift). Start the engine, put it in gear, and then try to hold one front wheel while you rev the throttle.

My 1997 Prairie 400 and 1998 Suzuki 500 had practically zero pull. It was very easy to hold one front wheel with one hand, while the other front wheel spins madly. Naturally, both of these machines where tight turners and easy to steer. Both Hondas pull harder (1997 300, 1999 450), but not hard enough to make a real difference. I could still prevent either front wheel from rotating, and still using only one hand. If you try this with a Polaris AWD, or any quad having a locked front axle, you cannot hold either front wheel once you start revving the engine.

"Simple" limited-slip differentials are quite different from "torque-sensing" differentials. The former includes a relatively simple clutch pack with springs connecting the two front drive axles. The clutch pack offers resistance which tries to keep both drive axles turning at the same RPM. The more spring pressure, the more resistance, and the more efficient the limited slip differential will be. But the more pressure you use in the clutch pack, the harder it will be to steer, and the more tiring it will be to your hands, wrists, and arms.

For easier steering but a less efficient limited slip differential, add GM or FoMoCo "Friction Modifier" to the differential oil. This will reduce the friction and the effectiveness of the already weak limited slip clutch pack. For more efficient limited slip action, but stiffer steering, use non-synthetic gear oil and no friction modifier.

For even more efficient limited slip action, but noticeably stiffer steering, you can shim the springs in the limited slip clutch pack, or force an extra clutch plate or disk into the clutch pack. We do the latter for drag racing cars with limited-slip rear ends. They sometimes chatter like hell when cornering on the street, but it works great to keep both tires spinning off the line at the drag strip.

Since a locked front end will be tiring and hard to steer ALL the time, and the benefits of a locked front axle will only be appreciated in extreme circumstances, I'm staying with the standard limited slip in order to enjoy the whole day's ride without early fatigue. I've ridden a Suzuki King Quad with the front axle locked, and I've ridden several Polaris AWD's with the front hubs locked, and I don't like the stiff and difficult steering... AT ALL!

I'm not going to debate the "3WD" issue. I don't believe there is any such thing in four-wheel ATV's, and I consider it nothing more than poorly devised ad hype terminology from Polaris. I still have a 1997 Polaris ATV brochure in which they describe chain-drive as the "superior drive system" when describing their chain-drive models, and then on a different page within the same brochure, they describe shaft-drive as the "superior drive system" when describing the shaft-drive Sportsman 500. I've always appreciated this display of "Polaris honesty and integrity". To me, it fits them well. And Suzuki isn't much better, lying about the ground clearance of their quads, and lying about the effectiveness of the limited slip differential on their new 50''s. It's different alright, but it's not a bit better.

The Bombardier Traxter appears to have the best front differential system right now, but I'm totally in the dark about Honda's new AP front differential. I'm looking forward to testing one. As Suzuki has already demonstrated, "saying" it works better doesn't mean it really does. Lying is easier than engineering.

Gordon Banks
Huntsville, AL

 

This past week i had a chance to ride a Xpedition 425. First of all it definately had a smoother ride than my Rancher but that was it.For having almost a 100cc advantage in displacement over the Rancher it did not accelerate as strong as my Rancher nor did it handle nearly as good and the egronomics felt weird.I also noticed that it had an open "U" joint on the shaft coming out the rear of the engine with no protection from water.As for the Ranchers AP front differential i myself preformed several tests to see how it works.First of all i tied it to a tree and it left four deep ruts from all four wheels spinning.Next i balanced it on a log large enough to elevate all four wheels and tilted it forward and after digging two ruts the front wheels pulled me off the log.Next i put it on the log off camber and shifted my weight so only one wheel got traction and the other was in the air,the wheel in the air stopped spinning and the one on the ground after digging a rut finally pulled me off the log without the help of the other three wheels.You Polaris owners obviously don't know what your are talking about when you refer to the Rancher as only a 3x4.It seems that Polaris owners are just trying to bash something that they no nothing about.Until you can prove otherwise the Rancher seems to have a great 4wd system.It is easy to steer and has a tight turning radius for a fulltime 4x4.

 

Gordon, I've noticed you commented on Polaris's stiff and difficult steering. You got that right! I don't know why they turn so hard, but being a machine with a 2wd option, you'd think they would turn easier than a Suzuki King Quad in differential lock! It must be the weight, or the steering design ain't much. For one thing, I know Honda uses bearings at the bottom of the steering stem, does Polaris use bushings? I've drove a Magnum 425 2x4 a lot at the place I used to work. They have 2 quads, a new '97 Magnum 2x4 and '90 Trailboss 2x4. The Trailboss turns probably twice as easy as the Magnum, and they're both a 2 wheel drive!! The owner said he prefers riding the old Trailboss over the new Magnum just because of the easier steering.